1. Field of the Invention
The present invention relates to a color image display device for displaying a color image.
2. Description of the Related Art
Hitherto, in a color image display device for displaying a color image, mixed colors are represented in such a manner that pixels of three primary colors of R (red), G (green) and B (blue) are closely disposed and the pixels are miniaturized. However, when there are displayed a white character of black in a background and reversely a black character of white in a background, it happens that color bleeding occurs on a boundary portion between the background and the characters, because the pixels of three primary colors of R, G and B are independently of one another.
Resolution of a color image display device, which now comes into wide use as a computer use, is generally 1024xc3x97768 pixels or so, or about one and a half times as much as 1024xc3x97768 pixels or so. With such an extent of resolution the color bleeding is not almost conspicuous. Recently, however, resolution of a color image display device is enhanced and there has been developed a high class of display device with 4000 pixels in long side. It often happens that such a high resolution of color image display device is used in a medical field and a field of the proof use for printing, and in such utilization fields, there is needed a higher definition of color image display device. Particularly, in the printing field, it often happens that black characters are often used in white background, and thus a quality of color representation of characters is a very important element.
Generally, in a color display device, it often happens that pixels of RGB are regularly arranged, for example, R, G, B, R, G, B, . . .
FIG. 2 is a view showing a pixel arrangement pattern of a conventional color image display device.
FIG. 2 shows a state that pixels of RGB are regularly arranged in the arrow X direction, like, R, G, B, R, G, B, . . . , and are regularly arranged in the arrow Y direction, like, R, R, R, . . . , G, G, G, . . . , B, B, B, . . . In the event that a display of white characters is performed using a color image display having such a pixel arrangement pattern, for example, there is provided such a display that the left end of a non-emissive area 41 expressed by hatched lines in FIG. 2 is subjected to edging of blue owing to an effect of light emission of B pixels 42a of the right end of a character display area 42 at the left side adjacent to the non-emissive area 41. Likely, there is provided such a display that the right end of the non-emissive area 41 is subjected to edging of red owing to an effect of light emission of R pixels 43a of the left end of the character display area 43 at the right side adjacent to the non-emissive area 41. Those regular color bleedings are conspicuous, and thus this is not suitable for the utilization field requiring a strict color representation.
In order to reduce the color bleeding as mentioned above, there is proposed a color image display device in which RGB pixels are arranged in such a manner that RGB pixels are shifted for each line one by one in pixel. In this case, however, there will occur a boundary line of a color bleeding in a slanting direction, and thus this is also conspicuous. Further, there is also proposed a color image display device in which three pixels of RGB are gathered as a triangle to provide pixel units, and the pixel units are regularly arranged. However, also in this case, there will occur a boundary line of a color bleeding in a slanting direction.
In view of the foregoing, it is an object of the present invention to provide a color image display device capable of preventing occurrence of color bleeding.
To achieve the above-mentioned object, the present invention provides a color image display device wherein a number of pixel units, each consisting of emitters for emitting color lights of red, green and blue, are arranged on a two-dimensional basis, and control of turn on of the emitters constituting a number of pixel units displays a color image, said color image display device comprising:
optical diffusive layers covering fronts of the associated emitters, respectively, said optical diffusive layers being mutually separated for each of the pixel units.
It is noted that the above-mentioned emitters include not only ones emitting color lights of red, green and blue, but also ones in which a color filter is mounted on a liquid crystal and a color filter is mounted on a white color light emitting pixel.